Terminal boards for WebControl
- Thread starter rossw
- Start date
Great, glad they've turned up (finally!!)swaggy said:
Prototyping area was intended for all those things you hang resistors and zeners out in mid air, or on bits of perfboard for. I used some for input dividers (I wanted to monitor my solar voltages from 0-150 VDC), one of the other guys who got boards has used it to make a zener diode "suppressed-zero" scale input, he was only interested in the range from 20 to 30V, so a 20V zener and a couple of resistors and a filter cap went there.
I haven't done it, but it's a trivial change to set the opamps reference to 5V so you can read +/- inputs with an offset zero. The spare opamp in the package can be set with a trimpot or precision reference on the prototyping area, and then used as a reference for the other amp channels.
I also brought out the Gnd and +V to two pads on the prototyping area where you could solder a terminal strip if you chose to run the opamp on a higher voltage than the 5V from the WC board itself (or use the +5V in the proto area to power something there).
Basically, it was an area of board I needed to have because of the screw connectors and rather than just wasting it, made it into an area you could use to tidy up the rest of your installation from the odd discrete component or two.
I'm mostly happy with the new boards.
I've put a rough web page together so I can keep notes, updates, pictures etc in one place.
http://webcontrol.rossw.net
I've put a rough web page together so I can keep notes, updates, pictures etc in one place.
http://webcontrol.rossw.net
I tried, but the system says you cannot use the messaging system!
Shipping a kit to Canada is fine.
One "long" kit $15. If you'd like the regulator, heatsink, screw and extra capacitors add $2.
Postage for regular airmail is $2.35. (All prices in Australian Dollars).
Got everything in stock for prompt despatch. Can you e-mail me your postal address details to cainetworks at rossw dot net
I've created a couple of new web pages. They're not elegant, but they're functional. Feedback and comments, ideas for improvements, corrections etc welcome!
The first http://webcontrol.rossw.net/WebAmpV2/assembly.html is assembly instructions for those who order unassembled kits.
The second, http://webcontrol.rossw.net/buynow.htm is an online ordering page. The range of products offered will evolve over time with availability of parts.
I will be offering some stand-alone 4-channel amplifier boards shortly, and other stuff I haven't announced yet.
The first http://webcontrol.rossw.net/WebAmpV2/assembly.html is assembly instructions for those who order unassembled kits.
The second, http://webcontrol.rossw.net/buynow.htm is an online ordering page. The range of products offered will evolve over time with availability of parts.
I will be offering some stand-alone 4-channel amplifier boards shortly, and other stuff I haven't announced yet.
CAI_Support
Senior Member
Nice job, Ross!
Hmmm, I want to power my board off the 24v from PLC. The V+ is straight thru to the soic. Does that need more than 5v or can I cut the trace and jumper from the out to the V+ tracefor the SOIC and analog? Currently when testing I'm seeing 22v on the analog in. Not real excited about connecting it to the WC.
todster said:
The chip is an LM2902. Please have a look at the chip itself to confirm which manufacturer's device is on your board. They are typically rated for 30V maximum in a single-supply situation such as you have, so should be ok.
The only warning I would make is that the amplifiers don't have a clamp, so if you have the gain set to (say) 10, and you apply 3V to the input, the amplifier output will try to drive to 30V (limited by the supply voltage). That entire 22 volts odd will be applied to the WebControl input. That is probably ok on the standard WC board with the 10V input and diode clamp - but I'd like to hear from CAI on that
As for how to do it - I don't think I sent you a board with the regulator, so the 5V from the WC board is directly connected to the opamp supply. The board was built with this in mind however, so it's a simple mod to change. Take a SHARP blade. Between the 16-pin header and the V+ terminal on the analog inputs is where the regulator would go, and there is a track on the component side of the board that jumps in+out. It's a fairly wide track, with a narrow link in the middle designed to be cut. Remove the short, thin bit in the middle and your high voltage V+ for the opamp is now isolated from the 5V WebControl board supply.
Cheers,
RossW
I didn't clearly explain. I have the 7805. I cut the trace and installed it. I'm powering it with 24Vdc from the PLC I'll be serially talking to. I jumpered from the 5V output of the 7805 to the power to the analog amp. I currently have no plans to use the analog but may in the future. Currently the analog with the 5V applied outputs a static 3.6v with nothing connected to the board and not connected to the WC.
I already scratched it between the cap and the V+ ( where it says GND TP1). I already scratched where indicated when I installed the 7805. From what I can tell the 7805 still feeds 5v to the WC on pin 13. I don't mind feeding the W/C the 5V as long as I know that the common source for both is exactly that, common. Which is why I want to get a 7808 or something along that line to power the WC and the RW breakout board from the 7808.
I already scratched it between the cap and the V+ ( where it says GND TP1). I already scratched where indicated when I installed the 7805. From what I can tell the 7805 still feeds 5v to the WC on pin 13. I don't mind feeding the W/C the 5V as long as I know that the common source for both is exactly that, common. Which is why I want to get a 7808 or something along that line to power the WC and the RW breakout board from the 7808.
